js-collection-iterator.h

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// Copyright 2019 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#ifndef V8_OBJECTS_JS_COLLECTION_ITERATOR_H_
#define V8_OBJECTS_JS_COLLECTION_ITERATOR_H_
 
#include "src/common/globals.h"
#include "src/objects/js-objects.h"
#include "src/objects/objects.h"
#include "src/objects/smi.h"
 
// Has to be the last include (doesn't have include guards):
#include "src/objects/object-macros.h"
 
namespace v8 {
namespace internal {
 
#include "torque-generated/src/objects/js-collection-iterator-tq.inc"
 
class JSCollectionIterator
    : public TorqueGeneratedJSCollectionIterator<JSCollectionIterator,
                                                 JSObject> {
 public:
  void JSCollectionIteratorPrint(std::ostream& os, const char* name);
 
  TQ_OBJECT_CONSTRUCTORS(JSCollectionIterator)
};
 
// OrderedHashTableIterator is an iterator that iterates over the keys and
// values of an OrderedHashTable.
//
// The iterator has a reference to the underlying OrderedHashTable data,
// [table], as well as the current [index] the iterator is at.
//
// When the OrderedHashTable is rehashed it adds a reference from the old table
// to the new table as well as storing enough data about the changes so that the
// iterator [index] can be adjusted accordingly.
//
// When the [Next] result from the iterator is requested, the iterator checks if
// there is a newer table that it needs to transition to.
template <class Derived, class TableType>
class OrderedHashTableIterator : public JSCollectionIterator {
 public:
  // Whether the iterator has more elements. This needs to be called before
  // calling |CurrentKey| and/or |CurrentValue|.
  bool HasMore();
 
  // Move the index forward one.
  void MoveNext() { set_index(Smi::FromInt(Smi::ToInt(index()) + 1)); }
 
  // Returns the current key of the iterator. This should only be called when
  // |HasMore| returns true.
  inline Tagged<Object> CurrentKey();
 
 private:
  // Transitions the iterator to the non obsolete backing store. This is a NOP
  // if the [table] is not obsolete.
  void Transition();
 
  OBJECT_CONSTRUCTORS(OrderedHashTableIterator, JSCollectionIterator);
};
 
}  // namespace internal
}  // namespace v8
 
#include "src/objects/object-macros-undef.h"
 
#endif  // V8_OBJECTS_JS_COLLECTION_ITERATOR_H_